#!/usr/bin/env python3

"""
    lldpmgrd

    LLDP manager daemon for SONiC

    Daemon which listens for changes in the PORT table of the State DB
    and updates LLDP configuration accordingly for that port by calling
    lldpcli.

    TODO: Also listen for changes in DEVICE_NEIGHBOR and PORT tables in
          Config DB and update LLDP config upon changes.
"""


try:
    import os
    import subprocess
    import sys
    import time

    from sonic_py_common import daemon_base
    from swsscommon import swsscommon
    from sonic_py_common.interface import inband_prefix, recirc_prefix, backplane_prefix
    from sonic_py_common import device_info
except ImportError as err:
    raise ImportError("%s - required module not found" % str(err))

VERSION = "1.0"

SYSLOG_IDENTIFIER = "lldpmgrd"
PORT_INIT_TIMEOUT = 300
FAILED_CMD_TIMEOUT = 6
RETRY_LIMIT = 5


class LldpManager(daemon_base.DaemonBase):
    """
    Class which subscribes to notifications of changes in the PORT table of
    the Redis State database and updates LLDP configuration accordingly for
    that port by calling lldpcli.
    Attributes:
        state_db: Handle to Redis State database via swsscommon lib
        config_db: Handle to Redis Config database via swsscommon lib
        pending_cmds: Dictionary where key is port name, value is pending
                      LLDP configuration command to run 
                      and the last timestamp that this command was failed (used for retry mechanism)
    """
    REDIS_TIMEOUT_MS = 0

    def __init__(self, log_identifier):
        super(LldpManager, self).__init__(log_identifier)

        # Open a handle to the Config database
        self.config_db = swsscommon.DBConnector("CONFIG_DB",
                                                self.REDIS_TIMEOUT_MS,
                                                False)

        # Open a handle to the Application database
        self.appl_db = swsscommon.DBConnector("APPL_DB",
                                              self.REDIS_TIMEOUT_MS,
                                              False)

        # Open a handle to the State database
        self.state_db = swsscommon.DBConnector("STATE_DB",
                                              self.REDIS_TIMEOUT_MS,
                                              False)
        
        self.pending_cmds = {}
        self.hostname = "None"
        self.mgmt_ip = "None"

        self.device_table = swsscommon.Table(self.config_db, swsscommon.CFG_DEVICE_METADATA_TABLE_NAME)
        self.port_table = swsscommon.Table(self.config_db, swsscommon.CFG_PORT_TABLE_NAME)
        self.mgmt_table = swsscommon.Table(self.config_db, swsscommon.CFG_MGMT_INTERFACE_TABLE_NAME)
        self.app_port_table = swsscommon.Table(self.appl_db, swsscommon.APP_PORT_TABLE_NAME)
        self.state_port_table = swsscommon.Table(self.state_db, swsscommon.STATE_PORT_TABLE_NAME)

        self.port_config_done = False
        self.port_init_done = False

    def update_hostname(self, hostname):
        cmd = ["lldpcli", "configure", "system", "hostname", hostname]
        self.log_debug("Running command: '{}'".format(cmd))

        proc = subprocess.Popen(cmd,stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        (stdout, stderr) = proc.communicate()

        if proc.returncode != 0:
            self.log_warning("Command failed '{}': {}".format(cmd, stderr))
        else:
            self.hostname = hostname

    def update_mgmt_addr(self, ip):
        if ip == "None":
            cmd = ["lldpcli", "unconfigure", "system", "ip", "management", "pattern"]
            self.log_info("Mgmt IP {0} deleted".format(self.mgmt_ip))
        else:
            cmd = ["lldpcli", "configure", "system", "ip", "management", "pattern", ip]
            self.log_info("Mgmt IP changed old ip {0}, new ip {1}".format(self.mgmt_ip, ip))

        self.log_debug("Running command: '{}'".format(cmd))

        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        (stdout, stderr) = proc.communicate()

        if proc.returncode != 0:
            self.log_warning("Command failed '{}': {}".format(cmd, stderr))
        else:
            self.mgmt_ip = ip

    def is_port_up(self, port_name):
        """
        Determine if a port is up or down by looking into the netdev_oper_status for the port in
        PORT TABLE in the State DB
        """
        # Retrieve all entires for this port from the Port table
        (status, fvp) = self.state_port_table.get(port_name)
        if status:
            # Convert list of tuples to a dictionary
            port_table_dict = dict(fvp)

            # Get the oper-status for the port
            if "netdev_oper_status" in port_table_dict:
                port_oper_status = port_table_dict.get("netdev_oper_status")
                return port_oper_status == "up"
            else:
                return False
        else:
            return False

    def generate_pending_lldp_config_cmd_for_port(self, port_name, port_table_dict):
        """
        For port `port_name`, look up the description and alias in the Config database,
        then form the appropriate lldpcli configuration command and run it.
        """
        port_desc = None

        # Skip special (recirc/inband) and backplane interfaces as we don't enable lldp on those interfaaces.
        if any([port_name.startswith(inband_prefix()),port_name.startswith(recirc_prefix()),port_name.startswith(backplane_prefix())]):
            return
 
        # Get the port alias. If None or empty string, use port name instead
        port_alias = port_table_dict.get("alias")
        if not port_alias:
            self.log_info("Unable to retrieve port alias for port '{}'. Using port name instead.".format(port_name))
            port_alias = port_name
        
        # Get the port description. If None or empty string, we'll skip this configuration
        port_desc = port_table_dict.get("description")
        
        lldpcli_cmd = ["lldpcli", "configure", "ports", port_name, "lldp", "portidsubtype", "local", port_alias]

        # if there is a description available, also configure that
        if port_desc:
            lldpcli_cmd += ["description", port_desc]
        else:
            self.log_info("Unable to retrieve description for port '{}'. Not adding port description".format(port_name))

        # Add the command to our dictionary of pending commands, overwriting any
        # previous pending command for this port
        self.pending_cmds[port_name] = { 'cmd': lldpcli_cmd, 'failed_count': 0}

    def process_pending_cmds(self):
        # List of port names (keys of elements) to delete from self.pending_cmds
        to_delete = []

        for (port_name, port_item) in self.pending_cmds.items():
            cmd = port_item['cmd']

            # check if linux port is up
            if not self.is_port_up(port_name):
                self.log_info("port %s is not up, continue"%port_name)
                continue
                
            if 'failed_timestamp' in port_item and time.time()-port_item['failed_timestamp']<FAILED_CMD_TIMEOUT:
                continue

            self.log_debug("Running command: '{}'".format(cmd))
            rc, stderr = run_cmd(self, cmd)
            # If the command succeeds, add the port name to our to_delete list.
            # We will delete this command from self.pending_cmds below.
            # If the command fails, log a message, but don't delete the command
            # from self.pending_cmds, so that the command will be retried the
            # next time this method is called.
            if rc == 0:
                to_delete.append(port_name)
            else:
                if port_item['failed_count'] >= RETRY_LIMIT:
                    self.log_error("Command failed '{}': {} - command was failed {} times, disabling retry".format(cmd, stderr, RETRY_LIMIT+1))
                    # not retrying again
                    to_delete.append(port_name)
                else:
                    self.pending_cmds[port_name]['failed_count'] += 1
                    self.pending_cmds[port_name]['failed_timestamp'] = time.time()
                    self.log_info("Command failed '{}': {} - cmd failed {} times, retrying again".format(cmd, stderr, self.pending_cmds[port_name]['failed_count']))
                    
        # Delete all successful commands from self.pending_cmds
        for port_name in to_delete:
            self.pending_cmds.pop(port_name, None)

    def lldp_get_mgmt_ip(self):
        mgmt_intf_keys = self.mgmt_table.getKeys()
        ipv4_addr = "None"
        ipv6_addr = "None"
        for key in mgmt_intf_keys:
            if '|' in key:
                key = key.split('|', 1)
                if '/' in key[1]:
                    ip = key[1].split('/', 1)
                    if self.mgmt_ip != ip[0]:
                        if '.' in ip[0]:
                            ipv4_addr = ip[0]
                        else:
                            ipv6_addr = ip[0]

        if ipv4_addr != "None":
            return ipv4_addr
        elif ipv6_addr != "None":
            return ipv6_addr
        else:
            return "None"

    def lldp_process_mgmt_info_change(self, op, mgmt_dict, key):
        if not op in ["SET", "DEL"]:
            return
        self.log_info("Mgmt Config Opcode: {} Dict {} Key {} Curr {}".format(op, mgmt_dict, key, self.mgmt_ip))
        if '|' in key:
            key = key.split('|', 1)
            if '/' in key[1]:
                ip = key[1].split('/', 1)
                if op == "DEL":
                    if self.mgmt_ip == ip[0]:
                        ip_addr = self.lldp_get_mgmt_ip()
                        self.update_mgmt_addr(ip_addr)
                else:
                    if not self.mgmt_ip == ip[0]:
                        if '.' in ip[0]:
                            self.update_mgmt_addr(ip[0])
                        elif '.' not in self.mgmt_ip:
                            self.update_mgmt_addr(ip[0])

    def lldp_process_device_table_event(self, op, device_dict, key):
        if not op in ["SET", "DEL"]:
            return
        self.log_info("Device Config Opcode: {} Dict {} Key {}".format(op, device_dict, key))
        try:
            hostname = device_dict["chassis_hostname"]
        except:
            hostname = device_dict.get("hostname")
        if not self.hostname == hostname:
            self.log_info("Hostname changed old {0}, new {1}".format(self.hostname, hostname))
            self.update_hostname(hostname)

    def lldp_process_port_table_event(self, key, op, fvp):
        if (key != "PortInitDone") and (key != "PortConfigDone"):
            if op == "SET":
                if fvp:
                    if "up" in dict(fvp).get("oper_status",""):
                        self.generate_pending_lldp_config_cmd_for_port(key, dict(fvp))
                    else:
                        self.pending_cmds.pop(key, None)
            elif op == "DEL":
                self.pending_cmds.pop(key, None)
            elif op:
                self.log_error("unknown operation '{}'".format(op))
        elif key == "PortInitDone":
            self.port_init_done = True
        elif key == "PortConfigDone":
            self.port_config_done = True

    def run(self):
        """
        Subscribes to notifications of changes in the PORT table
        of the Redis Config/Application database.
        Subscribe to APP_DB - get port oper status
        Subscribe to CONFIG_DB - get notified of port config changes
        Update LLDP configuration accordingly.
        """
        self.log_info("Starting up...")

        if not os.geteuid() == 0:
            self.log_error("Must be root to run this daemon")
            print("Error: Must be root to run this daemon")
            sys.exit(1)

        # Set select timeout to 10 seconds
        SELECT_TIMEOUT_MS = 1000 * 10

        # Daemon is paused on the configuration file to avoid lldp packets with wrong information
        # until all interfaces are well configured on lldpd
        resume_lldp_sent = False
        start_time = time.time()

        sel = swsscommon.Select()

        # Subscribe to PORT table notifications in the App DB
        sst_appdb = swsscommon.SubscriberStateTable(self.appl_db, swsscommon.APP_PORT_TABLE_NAME)
        sel.addSelectable(sst_appdb)

        # Subscribe to MGMT PORT table notifications in the Config DB
        sst_mgmt_ip_confdb = swsscommon.SubscriberStateTable(self.config_db, swsscommon.CFG_MGMT_INTERFACE_TABLE_NAME)
        sel.addSelectable(sst_mgmt_ip_confdb)

        # Subscribe to DEVICE_METADATA table notifications in the Config DB
        sst_device_confdb = swsscommon.SubscriberStateTable(self.config_db, swsscommon.CFG_DEVICE_METADATA_TABLE_NAME)
        sel.addSelectable(sst_device_confdb)

        # Listen for changes to the PORT table in the CONFIG_DB and APP_DB
        while True:
            (state, selectableObj) = sel.select(SELECT_TIMEOUT_MS)

            if state == swsscommon.Select.OBJECT:
                if selectableObj.getFd() == sst_mgmt_ip_confdb.getFd():
                    (key, op, fvp) = sst_mgmt_ip_confdb.pop()
                    self.lldp_process_mgmt_info_change(op, dict(fvp), key)
                elif selectableObj.getFd() == sst_device_confdb.getFd():
                    (key, op, fvp) = sst_device_confdb.pop()
                    self.lldp_process_device_table_event(op, dict(fvp), key)
                elif selectableObj.getFd() == sst_appdb.getFd():
                    (key, op, fvp) = sst_appdb.pop()
                    self.lldp_process_port_table_event(key, op, fvp)
                else:
                    self.log_error("Got unexpected selectable object")

            # Process all pending commands
            self.process_pending_cmds()

            # Resume the daemon since all interfaces data updated and configured to the lldpd so no miss leading packets will be sent
            if not resume_lldp_sent:
                if check_timeout(self, start_time):
                    self.port_init_done = self.port_config_done = True
            if self.port_init_done and self.port_config_done:
                self.port_init_done = self.port_config_done = False
                rc, stderr = run_cmd(self, ["lldpcli", "resume"])
                if rc != 0:
                    self.log_error("Failed to resume lldpd with command: 'lldpcli resume': {}".format(stderr))
                    sys.exit(1)
                resume_lldp_sent = True

# ============================= Functions =============================


def main():
    # Instantiate a LldpManager object
    lldpmgr = LldpManager(SYSLOG_IDENTIFIER)

    # Log all messages from INFO level and higher
    lldpmgr.set_min_log_priority_info()

    lldpmgr.run()


def run_cmd(self, cmd):
    proc = subprocess.Popen(cmd, universal_newlines=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    (stdout, stderr) = proc.communicate()
    return proc.returncode, stderr


def check_timeout(self, start_time):
    if time.time() - start_time > PORT_INIT_TIMEOUT:
        if device_info.is_frontend_port_present_in_host():
            self.log_error("Port init timeout reached ({} seconds), resuming lldpd...".format(PORT_INIT_TIMEOUT))
        return True
    return False


if __name__ == "__main__":
    main()
